- To play mods you will need to already have rFactor installed on your computer.- Install only one mod, if you install many mod there will be some problem in the game. In order to install another mod, just uninstall the mod and install the new mod.- Install of RFT 2008 V3.1 is not needed if you want to play RFT 2008 V2 and install of RFT 2008 V2 is not needed if you want to play RFT 2008 V3.1. These are seperate mods.